Sigla vs. Sigma

The signs, abbreviations, letters, or characters standing for words, shorthand, etc., in ancient manuscripts, or on coins, medals, etc.

The eighteenth letter of the Classical and Modern Greek alphabets, the twentieth letter of Old and Ancient.

(mathematics) The symbol Σ, used to indicate summation of a set or series.

(statistics) The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.

The Greek letter

the 18th letter of the Greek alphabet

Sigma (uppercase Σ, lowercase σ, lowercase in word-final position ς; Greek: σίγμα) is the eighteenth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 200.